We'd avoid · Synthetic antioxidant

BHA and BHT

Also appears on labels as: BHA preservative

Synthetic phenolic antioxidants that keep fats from oxidizing, far more durably than vitamin E does.

Watched ingredients get highlighted on every product panel you open.

Where it comes from: Chemical synthesis.
Why it's in the product: Extends shelf life, especially in fat sprayed onto kibble after extrusion.
Safety and toxicity: The International Agency for Research on Cancer classifies BHA as possibly carcinogenic to humans based on high-dose rodent studies, and it appears on California's Prop 65 list. Levels in pet food are far below those study doses. Our objection is exposure pattern: pets eat the same food daily for years, and mixed tocopherols do the same job without the question mark.
Interactions and who should be careful: None established at food levels.

What the research says

BHA keeps fats from going rancid. The International Agency for Research on Cancer lists it as possibly carcinogenic to humans based on tumor findings in high-dose rodent studies, and California's Prop 65 list includes it.

The dose in pet food is far below study levels, but pets eat the same food every day for years, and mixed tocopherols (vitamin E) preserve fat without the question marks. Many premium brands have already dropped BHA, which tells you it isn't necessary.

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General reference, not veterinary advice. Dose, breed, and existing conditions change the answer, so talk to your vet before changing what your pet eats. Think we got this wrong? Tell us and we log it publicly.